Amy Grossberg

WILMINGTON, Delaware (CNN) -- Lawyers for Amy Grossberg, who pleaded guilty in July to manslaughter in the 1996 death of her newborn son, on Tuesday sought to have her 30-month jail sentence reduced.

In papers filed in the Delaware Superior Court, Grossberg, 20, of Bergen County, New Jersey, asked Judge Henry du Pont Ridgely to consider a motion for reducing the time she must serve in the Baylor Women's Prison outside Wilmington.

Grossberg has been a "model inmate" since she was imprisoned July 9, according to a request filed Monday to reduce her 2 1/2-year sentence.

Her attorney, John Malik, said Grossberg volunteered for work duties right away, enrolled in college correspondence classes in English and psychology, and is working with a foundation on a computer game to help teen-agers make better choices.

"Amy has volunteered her assistance ... as a way to help other young girls deal with important issues such as sex and pregnancy and make appropriate choices when it comes to these issues," Malik wrote.

The filing included a letter from Grossberg in which she described her progress in the college courses and her work as a custodian in the prison.

She also asked to be able to perform her mandated 300 hours of community service work in a New Jersey-based program for pregnant women and their babies called Several Sources Foundation.

Grossberg and her boyfriend, Brian Peterson, 20, were high school sweethearts in the well-to-do New Jersey suburb of Wyckoff.

Both were both charged with first-degree murder when the body of their newborn son was found in a Dumpster behind a motel where Grossberg gave birth with Peterson's help.

Although they maintained the infant was born dead, the state medical examiner said it was killed by blunt force trauma to the head.

Peterson, who was sentenced to two years, said Grossberg told him to get rid of the baby's body. He threw it in a trash bin outside the motel.

Peterson's lawyer also filed for a reduced sentence, a process that must be done within 90 days after sentencing.

The Associated Press and Reuters contributed to this report.